Operating instructions

4-1. GENERAL.
All controls utilized during normal operation of
the Model PA300 are located on the front panel (see
figure 4-1).
The wired-in noise cancelling microphone
provides high quality voice reproduction in the public
address mode. The microphone push-to-talk switch
will override all siren functions, except radio rebroad-
cast, for instant PA use.
4-2. GAIN CONTROL.
The GAIN control is used to turn the siren on
and off. Also, it is used to control the volume when
the siren is used for public address or radio amplifi-
cation. Clockwise rotation of the knob increases voice
volume in the public address or radio amplification
mode. The GAIN control does not control the volume
of the siren signals.
The maximum clockwise setting of the control
will be determined, in most cases by the point at
which feedback or “squeal” occurs. This will depend
upon the microphone gain, open windows, speaker
placement, proximity of reflecting surfaces (building
or other vehicles), etc. Adjust the GAIN control to a
position just below the point at which feedback
occurs or as desired.
4-3. SELECTOR SWITCH.
The Selector switch is a five-position rotary
switch used to select the mode of operation. The
following are positions on the Selector switch.
Figure 4-1. Front View.
A. RADIO.
In this position, incoming radio messages
are amplified by the siren and rebroadcast over the
outside speaker.
B. MANUAL.
In this position, it is possible to operate the
siren by activating the HORN/SIREN switch. The
siren can also be activated by means of an auxiliary
switch, such as the horn ring button (refer to para-
graph 4-6).
C. WAIL.
In this position, the siren produces a
continuous “wailing” sound, up and down in fre-
quency.
D. YELP.
In this position; a continuous, rapid
“warbled” tone is generated.
E. HI-LO (Models 690000 and 690001).
In this position, a two-tone sound will be
heard. This distinctive tone may be reserved for any
special indication or situation.
F. PRIORITY (Models 690002 and 690004).
In this position, a rapid "YELP" sound will
be heard. This distinctive tone may be reserved for
any special indication or situation.
4-4. HORN/SIREN SWITCH.
The HORN/SIREN switch, located on the left
side of the front panel, activates the electronic air
horn sound (up) or peak-and-hold sound (down) in
any siren mode except radio.
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